BIS monitoring during midazolam and midazolam-ketamine conscious intravenous sedation for oral surgery

A Review of Bispectral Index Utility in Neurocritical Care Patients

Context: Bispectral Index (BIS) was introduced in 1960 to monitor the depth of anesthesia in the operating rooms. It has been recently used to monitor the sedation in the critically ill patients hospitalized in intensive care and neurocritical care units (NCCU). Evidence Acquisition: Patients in the NCCU, particularly those with prolonged mechanical ventilation require appropriate adjustments in the administration of sedative drugs. Similarly, those who require neuro protection with barbiturates need to be closely monitored in the depth of their coma. Results: BIS may be a useful tool in this situation, and it can also help shorten the duration of mechanical ventilation by determining the appropriate time to eliminate patients from mechanical ventilation. We conducted a literature search to evaluate the utility of BIS monitoring in the NCCU patients with subarachnoid hemorrhage, intracranial hemorrhage, coma, cerebral hypoxia, status epilepticus and traumatic brain injury. Conclusions: BIS monitoring may be a useful adjunct to take care of the patients. However, further studies with a larger population and better design are required to substantiate the role of BIS monitoring in the care of NCCU patients.

Evaluation of endovenous sedation using BIS monitoring in dentistry. A systematic review

Background

The aim of the present review was evaluate the utility and validity of the Bispectral Index (BIS) in dental treatment carried out under endovenous sedation, and compare its efficacy with clinical sedation scales.

Material and Methods

Electronic and manual literature searches were conducted by two independent reviewers for articles published up to April 2017 in several databases, including Medline and Cochrane Library.

Results

Sixteen articles met the inclusion criteria. A correlation was identified between BIS and clinical sedation scales. A BIS range between 75 and 84 showed a high probability of corresponding to an Observer’s Assessment of Alertness and Sedation Scale (OAA/S) value of 3; a scored 3 on the Ramsay scale corresponds around 85 on the BIS; while BIS values between 57 and 64 corresponded to a University of Michigan Sedation Scale value of 3. BIS monitoring provides continuous measurement of the patient’s hypnotic state or state of consciousness, awareness, and recall. It proved impossible to perform an analysis of statistical data drawn from the studies reviewed due to the disparity of inclusion criteria among the works.

Conclusions

BIS for sedation monitoring might make possible to evaluate sedation levels objectively in real time, reducing the dose of the sedative required, increasing safety, and minimizing secondary effects.

Key words:Bispectral analysis, BIS monitoring, intravenous sedation, dental treatment, anesthetics.

Modelling of the Sedative Effects of Propofol in Patients undergoing Spinal Anaesthesia: A Pharmacodynamic Analysis

Sedation can increase patient comfort during spinal anaesthesia. Understanding the relationship between the propofol effect-site concentration (Ce) and patient sedation level could help clinicians achieve the desired sedation level with minimal side effects. We aimed to model the relationship between the propofol Ce and adequate and deep sedation and also incorporate covariates. Thirty patients scheduled for orthopaedic surgery received spinal anaesthesia with 0.5% bupivacaine. Propofol was administered via an effect-site target-controlled infusion device using the Schnider pharmacokinetic model. The pharmacodynamic models for both adequate sedation [Observer's Assessment of Alertness/Sedation (OAA/S) scores of 3-4] and deep sedation (OAA/S scores of 1-2) were developed using nonlinear mixed-effects modelling. Increments in the propofol Ce were associated with increased depths of sedation. In the basic model, the estimated population Ce50 values for adequate and deep sedation were 0.94 and 1.52 μg/ml, respectively. The inclusion of the patient's age and sensory block level for adequate sedation and of age for deep sedation as covariates significantly improved the basic model by decreasing the objective function's minimum value from 10696.72 to 10677.92 (p = 0.0003). The simulated Ce50 values for adequate sedation in 20-year-old patients with a T12 sensory level and in 80-year-old patients with a T4 level were 1.63 and 0.53 μg/ml, respectively. Both age and sensory block level should be considered for adequate sedation, and the propofol concentration should be reduced for elderly patients with a high spinal block to avoid unnecessarily deep levels of sedation.

Sedation in oral and maxillofacial day care surgery: A comparative study between intravenous dexmedetomidine and midazolam

Introduction:

Sedation is an important component of day care oral and maxillofacial surgical procedures under local anesthesia. Although various sedative drugs in different regimens have been used for sedation, an ideal agent and regimen are yet to be established.

Aim:

The aim of this study is to compare the efficacy of intravenous (IV) dexmedetomidine and midazolam as a sedative agent for day care oral and maxillofacial surgical procedures.

Settings:

The study was conducted in the Department of Oral and Maxillofacial Surgery, SCB Dental College and Hospital, Cuttack, Odisha, India.

Materials and Methods:

A total of sixty adult patients of age group 18–65 years, of either sex were randomly selected equally in two groups for the study. One group named Group D received dexmedetomidine and the other named Group M received midazolam. Patients were evaluated for oxygen saturation (SPO₂), respiration rate (RR), systolic blood pressure (SBP), diastolic blood pressure (DBP), Ramsay sedation score, bispectral index (BIS) score, amnesia, Aldrete score, relaxation during the surgery, and drug preference.

Results:

Midazolam was associated with greater amnesia. Dexmedetomidine was associated with lower heart rate, SBP, and DBP. There was no significant difference in SPO₂, RR, Aldrete score, Ramsay sedation score, and BIS score between the two drugs. Patient preference and relaxation were more in dexmedetomidine group.

Conclusion:

IV dexmedetomidine is a comparable alternative to midazolam for sedation in day care oral and maxillofacial surgery under local anesthesia. It is the preferred drug when a lower heart rate and blood pressure or less amnesia is needed without any serious side effects.

The effects of bispectral index monitoring on hemodynamics and recovery profile in developmentally delayed pediatric patients undergoing dental surgery

BACKGROUND

General anesthesia is often preferred for dental surgery or rehabilitation in developmentally delayed pediatric patients. Bispectral index monitoring is used to monitor the depth of anesthesia and to ensure early recovery. However, studies on the topic in developmentally delayed pediatric patients are limited.

AIM

To evaluate the effects of Bispectral Index Scale (BIS) on hemodynamics and recovery profile in developmentally delayed pediatric patients undergoing dental surgery.

METHODS

Forty children between the ages of 6-16 years were studied in this prospective and randomized study. The children were randomized into two groups. In Group 1 (n = 20), general anesthesia was maintained with 1-2 minimum alveolar concentration (MAC) of sevoflurane in oxygen by standard practice. In Group 2 (n = 20), the depth of anesthesia was monitored by BIS. BIS values were continuously recorded from awake status to tracheal extubation. The duration of the surgical procedure, anesthesia, postanesthesia care unit (PACU) stay was noted. To evaluate recovery profile, time to spontaneous ventilation, extubation, open eyes, and PACU discharge were also noted.

RESULTS

There were significant differences between recovery times and Non-communicating Children's Pain Checklist - Postoperative Version (NCCPC-PV) scores of two groups. Time to spontaneous ventilation [Difference in means (95% CI); 3.17 (1.79-4.54) P < 0.001], extubation [Difference in means (95% CI); 3.13 (1.66-4.60) P < 0.001], open eyes [Difference in means (95% CI); 3.97 (2.34-5.59) P < 0.001], and PACU stay time [Difference in means (95% CI); 23.55 (18.08-29.01) P < 0.001] were significantly shorter in Group 2.

CONCLUSION

In conclusion, results suggest that routine BIS monitoring may be beneficial due to its favorable effects on the recovery profile in developmentally delayed pediatric patients.

The relationship between the Bispectral Index (BIS) and the Observer Alertness of Sedation Scale (OASS) scores during propofol sedation with and without ketamine: a randomized, double blinded, placebo controlled clinical trial

Prior studies have examined the static effect of intravenous ketamine on the BIS Index for sedation but it remains unknown if the BIS Index is a reliable method to track sedation levels in the presence of ketamine. The major objective of the current investigation was to compare the BIS Vista Index ability to track varying depths of sedation as determined by OASS scores in a standardized anesthetic regimen with and without ketamine. The study was a randomized, double blinded clinical trial. Patients undergoing breast surgery under sedation with propofol were randomized to receive ketamine (1.5 μg kg min(-1)) or saline. Infusion data was used to estimate propofol plasma concentrations (Cp). The main outcome of interest was the correlation between the BIS Vista Index with the OASS score. Twenty subjects were recruited and fifteen completed the study. Four hundred fifty-five paired data points were included in the analysis. Model performance (Nagelkerke R(2)) of the multinomial logistic regression model was 0.57 with the c-statistic of 0.87 (95 % CI 0.82-0.91). Compared to awake the odds ratio for BIS values predicting moderate sedation in the saline/propofol group 1.19 (95 % CI 1.12-1.25) but only 1.06 (95 % CI 1.02-1.1) in the ketamine/propofol group (P = 0.001). There was no difference in the odds for BIS values to predict deep sedation between groups (P = 0.14). The BIS monitor can be used to monitor sedation level even when ketamine is used with propofol as part of the sedation regimen. However, ketamine reduces the value of the BIS in predicting moderate sedation levels.

Ketamine pharmacology: an update (pharmacodynamics and molecular aspects, recent findings)

For more than 50 years, ketamine has proven to be a safe anesthetic drug with potent analgesic properties. The active enantiomer is S(+)-ketamine. Ketamine is mostly metabolized in norketamine, an active metabolite. During "dissociative anesthesia", sensory inputs may reach cortical receiving areas, but fail to be perceived in some association areas. Ketamine also enhances the descending inhibiting serotoninergic pathway and exerts antidepressive effects. Analgesic effects persist for plasma concentrations ten times lower than hypnotic concentrations. Activation of the (N-Methyl-D-Aspartate [NMDA]) receptor plays a fundamental role in long-term potentiation but also in hyperalgesia and opioid-induced hyperalgesia. The antagonism of NMDA receptor is responsible for ketamine's more specific properties. Ketamine decreases the "wind up" phenomenon, and the antagonism is more important if the NMDA channel has been previously opened by the glutamate binding ("use dependence"). Experimentally, ketamine may promote neuronal apoptotic lesions but, in usual clinical practice, it does not induce neurotoxicity. The consequences of high doses, repeatedly administered, are not known. Cognitive disturbances are frequent in chronic users of ketamine, as well as frontal white matter abnormalities. Animal studies suggest that neurodegeneration is a potential long-term risk of anesthetics in neonatal and young pediatric patients.

Bispectral index monitoring of sedation depth in pediatric dental patients

The bispectral index (BIS) monitor records electroencephalogram waveforms and provides an objective measure of the hypnotic effect of a sedative drug on brain activity. The aim of this pilot study was to use the BIS monitor to evaluate the depth of procedural sedation in pediatric dental patients and to assess if the BIS monitor readings correlate with a validated pediatric sedation scale, the University of Michigan Sedation Scale (UMSS), in determining the level of sedation in these patients. Thirty-five pediatric dental patients requiring sedation were studied prospectively. A baseline BIS reading was obtained and during the procedure an independent observer recorded the BIS every 5 minutes. The operator, who was blinded to the BIS results, determined the UMSS scale at the same 5-minute interval. The patients were monitored postoperatively for 1 hour. There was a significant but moderate correlation between BIS values and UMSS scores (Spearman's rank correlation r  =  -0.574, P < .0001). Percentage of agreement and kappa coefficient using all the observations were also calculated. The percentage of agreement was 37.8%, the kappa coefficient was 0.18 (P < .0001), and the weighted kappa coefficient 0.26 (P < .0001). A lack of correlation was noted between the deeper levels of UMSS sedation scores and BIS values. This study demonstrated a significant correlation between BIS values and the UMSS score in pediatric dental patients undergoing mild to moderate sedation. Based on our results, it appears that the BIS monitor may be useful during mild or moderate sedations to establish the level of sedation objectively without the need to stimulate the patient.

Effectiveness of premedication agents administered prior to nitrous oxide/oxygen

BACKGROUND AND OBJECTIVE

In paediatric dentistry, when anxiety, fear of dental procedures or behavioural impairment precludes the conduct of dental treatments, sedation procedures are required. However, sedation at the desired level might not be achieved despite administration of various agents. The present study aimed to evaluate the effectiveness of oral premedication with different agents on children scheduled for dental treatment under nitrous oxide/oxygen (N2O/O2) sedation.

METHODS

The present research was approved by the Ethics Committee of Gazi University Faculty of Medicine. Sixty children aged between 5 and 8 years, ASA I or II, having no mental or motor retardation, requiring at least two-visit dental treatment, having no sedation or general anaesthesia experience, and incompliant with dental treatment (Frankl Behaviour Scale>or=3), were enrolled into the study after obtaining informed parental consent. The children were then randomly assigned to one of four groups. The treatment regimen according to the study groups was as follows: oral administration of 1 mg kg(-1) hydroxyzine hydrochloride suspension (Atarax) 1 h preoperatively (group I, n=15), oral administration of 0.7 mg kg(-1) midazolam (Dormicum) 15 min preoperatively (group II, n=15), oral administration of 3 mg kg(-1) ketamine (Ketalar) with 0.25 mg kg(-1) midazolam (Dormicum) 15 min preoperatively (group III, n=15), and no oral premedication administration [group IV (controls), n=15]. Peripheral oxygen saturation (SpO2) and heart rate were monitored with a pulse oximeter during treatment. The sedation level was monitored with the bispectral index. Following premedication, 40% N2O and 60% O2 was administered to all groups by means of a nasal mask. Sedation depth was evaluated using the Ramsay Sedation Scale and data were recorded at 5 min intervals. Sedation success and other sedation-related events were recorded.

RESULTS

The evaluation of the findings of this study revealed that treatment procedures were completed without any serious complications. Achievement of sedation in terms of satisfactory/mid-level satisfactory/unsatisfactory was as follows: 13.3/53.3/33.3% in group I; 54/20/26% in group II; 33.3/33.3/33.3% in group III, and 6.7/60/33.3% in group IV, respectively. Ramsay Sedation Scale results revealed that the most effective medication was 0.7 mg kg(-1) midazolam.

CONCLUSION

It is concluded that 0.7 mg kg(-1) midazolam is more effective than 0.25 mg kg(-1) midazolam with 3 mg kg(-1) ketamine and 1 mg kg(-1) hydroxyzine hydrochloride in terms of oral premedication prior to N2O/O2 sedation in children scheduled for dental treatments.

Can analysis of the bispectral index prove helpful when monitoring titration of doses of midazolam and ketamine for sedation during paediatric cardiac catheterization

OBJECTIVE

We investigated the use of the bispectral index for monitoring sedation during cardiac catheterization. The scores for the bispectral index may not reflect correct values in children, but may be helpful during titration of sedatives such as midazolam and ketamine.

METHODS

We conducted a prospective randomized clinical trial in 126 patients scheduled for cardiac catheterization in a teaching hospital. They ranged in age from 4 months to 15 years. In 66 patients, sedation was performed without use of the bispectral index, while the index was used in the other 60 patients. The data collected included heart rate, mean arterial pressure, respiratory rate, saturation of oxygen, amount of sedatives, awakening time and adverse effects. We subdivided the patients into age-related groups for each parameter.

RESULTS

The demographic data were not statistically different. Monitoring with the bispectral index in those aged from 1 to 3 years revealed use of lower doses of midazolam, at 2.09 mg per kg per hr, with standard deviation of 0.36, and similarly lowers doses of ketamine, at 2.07 mg per kg per hr, with standard deviation of 0.22, the values in those not monitored being 2.93, with standard deviation of 0.45, and 2.96 with standard deviation of 0.51 respectively, these difference being statistically significant (p = 0.001 and p = 0.04, respectively). In those aged from 3 to 6 years of age, dosage of midazolam was 2.09, with deviation of 0.36, and of ketamine 1.78, with deviation of 0.27, following use of the bispectral index, compared to 2.89 with deviation of 0.28, and 2.62 with deviation of 0.69 respectively, when the bispectral index was not used, these again being significant differences (p = 0.033 and p = 0.04). The requirements for respiratory support and adverse effects were also significantly lower when using the bispectral index (p less than 0.05). No significant difference was found regarding dosages at the ages of 4 months to 1 year, and 6 to 15 years. The awakening time, however, was shorter with use of the index in those aged from 1 to 6 years.

CONCLUSIONS

When using the bispectral index for monitoring sedation during catheterization in children, we noted decreased need for doses of midazolam and ketamine, a lower need for respiratory support and less adverse effects.

Sedation and regional anaesthesia in the adult patient

This review discusses sedation for regional anaesthesia in the adult population. The first section deals with general aspects of sedation and shows that the majority of patients receiving sedation for regional anaesthesia are satisfied and would choose it again. Methods of assessing the level of sedation are discussed with emphasis on clinical measures. The pharmacology of the drugs involved in sedation is discussed, with propofol and remifentanil appearing to be the combination of choice for sedation in regional anaesthesia. The techniques for administering sedation are discussed and replacement of the traditional repeated boluses or continuous infusion with pharmacokinetic and patient-controlled systems is supported. Patient satisfaction studies suggest that patient-controlled systems are preferred.

Continuous infusion in adult females dogs submitted to ovariohysterectomy with midazolam-xylazine and/or medetomidine pre-treated with methotrimeprazine and buprenorphine

PURPOSE: To compare, by continuous infusion of ketamine or medetomidine combined to methotrimeprazine and buprenorphine, ketamine and midazolam, the degree of hypnosis, myorelaxation, anesthetic quality and surgical feasibility through evaluation of possible parametric alterations and recovery quality. METHODS: 20 healthy adult females dogs, aged 3 to 5 years, body weight between 7 and 15 kg, were assigned randomly and homogenously to 2 groups of 10 animals each (n=10), group 1 (G1) and group 2 (G2), respectively. Animals of G1 were subjected to a pre-treatment with intravenous 1.0 mg/kg methotrimeprazine and or 3ì/kg. After 15 minutes, a 5.0 mg/kg ketamine and 0.2 mg/kg midazolam were intravenously injected. Immediately after induction, an anesthetic combination of 0.4 mg/kg/h midazolam, 20 mg/kg/h ketamine and 1.0 mg/kg/h xylazine, was continuously and intravenously administered for 30 minutes. The same techniques were used in G2 except for the substitution of xylazine for 30ìg/kg/h medetomidine. RESULTS: In G1 there was a 1st and 2nd degree atrioventricular heart block, a longer recovery period and lower quality. In G2 a 1st degree atrioventricular heart block occurred but isolated and ephemeral. CONCLUSIONS: The continuous infusion method, besides reducing drugs utilization, prevented collateral effects allowing a more tranquil recovery with no excitations, both protocols permitted the surgical procedure (ovary-hysterectomy) bringing about a reduction in hypnosis and an accentuated myorelaxation. Xylazine and medetomidine showed a similar pharmacodynamic behavior but with different clinical aspects. The electrocardiographic alterations observed in G2 and in a lower degree in G1 must be well studied. Describers: dogs, ketamine, methotrimeprazine, medetomidine, midazolam and xylazine.

Update on bispectral index monitoring

Since 1997, bispectral index (BIS; Aspect Medical Systems Inc., Natick, MA) has been in clinical practice and a wealth of experimental research has accumulated on its use. Originally, the device was approved only for monitoring hypnosis and has now received an indication for reducing the incidence of intraoperative awareness during anesthesia. Numerous studies have documented the ability of BIS to reduce intermediate outcomes such as hypnotic drug administration, extubation time, postoperative nausea and shortened recovery room discharge. Two recent large-scale outcome studies using BIS (one randomized controlled trial and one prospective, nonrandomized historical cohort study) identified an approximately 80% reduction in the incidence of recall after anesthesia. BIS provides clinicians with unique information that can be used to tailor hypnotic drug doses to individual patient requirements. BIS does not predict movement or hemodynamic response to stimulation, nor will it predict the exact moment consciousness returns. This review will also discuss other BIS applications including use in pediatrics, intensive care and for procedural sedation. Some limitations exist to the use of BIS and it is not useful for some individual hypnotic agents (ketamine, dexmedetomidine, nitrous oxide, xenon, opioids). BIS technology is moving out of the operating room and into diverse environments where conscious and deep sedation are provided. Anesthesiologists need to be actively involved in promoting patient safety and helping transition this technology into broader use.

Monitoring of vital signs during dental care

Advances in medicine have greatly increased the survival of patients with severe health problems and have significantly prolonged life in elderly individuals with systemic disorders. Concomitant advances in dentistry and evolving societal expectations regarding dental health and function have likewise ensured that these patients are increasingly retaining their teeth and/or seeking dental care. The administration of local anaesthetics and the performance of extensive dental procedures may cause stress and systemic disturbances in such patients. In order to avoid potentially serious reactions, dentists are obligated to monitor continuously their medically challenged patients. Monitoring provides three important benefits. First, it helps the dentist detect acute medical emergencies that may require an immediate response. Second, monitoring may reveal gradual deleterious trends that can often be easily reversed before a true emergency occurs. Third, monitoring can assist the dentist in evaluating the efficacy of any emergency treatments or preventive measures that are rendered. The purposes of this article are to: briefly review monitoring techniques and devices, discuss their suitability for use in the dental office, and provide some tips for their application during dental care. In overall decreasing order of routine importance, monitoring resources include the following: responsible personnel, non-invasive blood pressure monitor, pulse oximeter, ECG, and the pretracheal stethoscope or capnograph.